Re: Edu versus Speakeasy Speedtest

[Robert Enger - NANOG <nanog () enger us>]

 1) The capacity that a campus has into I2 or NLR is different than the BW the campus purchases from their commercial 
provider(s).
2) The commercial BW test sites are not optimized for speed.  They do not have unlimited capacity network connections.  
And, they have not tuned their network stack for HS operation: notably, their OS will impose memory limits on the 
socket / transmit-buffer pool; so even if a receiver advertises a big window, frequently the transmitter (speed test 
server) will never queue enough data to fill the pipe
3) Peering capacity is not what it should be into the networks used by some of the BW test sites.



On 4/29/2010 8:53 AM, Murphy, William wrote:
> I work for an Edu with multi-gigabit Internet connectivity and I get
> questions from users saying "Why am I only getting 14Mb when I run this
> speed test?"  I have got to believe that the various Internet speed tests
> (Speakeasy or dslreports) are rate limited to prevent someone from shutting
> them down.  I am able to get 300-400Mb running from a PC inside my network
> to NDT servers located on Internet2, so that tells me my border and internal
> network is healthy.  Can someone on this list shed some light regarding
> reliability and accuracy of these various speed tests especially for an Edu
> with lots'o bandwidth?  Thanks.
>
>
>
> Bill Murphy
>
> University of Texas Health Science Center - Houston